This invention relates generally to fluid valves and more particularly to fluid valves having adjustable lifts for pumps.
In hydraulic pumping systems, check valves are typically used to limit-the direction of flow through a pump. As is known in the art, these valves include a ball closure element which, responsive to the direction of fluid movement through the valve, closes to prevent the passage of the fluid in one direction by moving into engagement with a valve seat and opens to permit the passage of the fluid in an opposite direction by moving away from the valve seat. In order to control the amount of fluid pressure that is permitted to flow through a valve, a ball stop element is generally used to limit the distance, commonly referred to as xe2x80x9clift,xe2x80x9d to which the ball closure element is permitted to move away from the valve seat.
An exemplary pump having check valves with ball stops that limit the lift of a ball closure element is shown in commonly assigned U.S. Pat. No. 5,647,737, the disclosure of which is incorporated herein by reference. A two-ball style pump available from Ingersoll-Rand Company, Woodcliff Lake, N.J. as the ARO Model 66475 pump incorporates such check valves having a ball closure element located within a cylindrical ball guide in its lower pump end to control the inlet flow of a fluid to be pumped into the pump. A pin positioned in holes located in a ball guide is used as a ball stop element to increase or decrease the lift of the ball valve element in the valve body. If more ball lift is desired for heavier (i.e., more viscous) fluids, the pin is moved to holes in the ball guide that are further away from the valve seat. Conversely, if less ball lift is desired for lighter (i.e., less viscous) materials, the pin is moved to holes located closer to the valve seat in the ball guide.
Manufacturing such check valves with adjustable lifts, however, require drilling or otherwise providing multiple sets of holes in the cylindrical ball guide for providing multiple positions into which a ball stop pin could be inserted.
The foregoing illustrates limitations known to exist in present devices and methods. Thus it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly an alternative packing assembly, retrofit kit, and check valve having an adjustable lift are provided that include the features more fully disclosed hereinafter.
According to the present invention, a packing assembly, retrofit kit, and check valve with adjustable lift are provided having a ball stop member having opposed first and second contact portions and at least two washers being provided in a stacking configuration. The stacking configuration is one selected from one in which all of the at least two washers are stacked against the first contact portion of the ball stop member, one in which all of the at least two washers are stacked against the second contact portion of the ball stop member, and one in which at least one of the at least two washers is stacked against the first contact portion of the ball stop member and at least one of the at least two washers is stacked against the second contact portion of the ball stop member. Preferably, the at least two washers are of different thicknesses with, more preferably, the thicknesses of the at least two washers being multiples of each other. Most preferably, the at least two washers are a first washer and a second washer with the second washer having a thickness that is twice the thickness of the first washer.